Circuit breaker panelboard



Nov. 3, 1964 R. T. CASEY CIRCUIT BREAKER PANELBOARD Filed March 29, 1956 y1 mum M v HW 1| immuni 1h l INVENTR. ROBERT T. CASEY HIS ATTORNEY United States Patent O 3,155,882 CIRCUIT BREAKER PANELBOARD Robert T. Casey, Southington, Conn., assigner to General Electric Company, a corporation of New York Filed Mar. 29, 1956, Ser. No. 574,850 7 Claims. (Cl. 317-119) My invention relates to circuit breaker panel boards and load centers and especially to such panelboards and load centers incorporating circuit breakers having at least one terminal thereof adapted to be connected by a plug-in type electrical connection. More speciiically, the present invention is concerned with an improvement upon plug-in circuit breaker paneiboards of the type disclosed in Patent No. 2,738,446, issued March 13, 1956, to William J. Fleming and assigned to the same assignee as the present invention.

The above application discloses a circuit breaker panelboard having a number of stations or locations, at each of which a circuit breaker may be mounted, electrical contact being made therewith by a plug-in action. Such circuit breakers are made in various ampere ratings, such as 15, 20, 3() and 50 amperes, the selection of a breaker of a given rating being dictated by the requirements of the circuit which it is used to protect,

The installation of such panelboards and the initial selection and installation of the various breakers is, of course, ordinarily carried out by qualilied personnel, and also is usually subject of inspection and approved by civil authorities. lt can, therefore, be assumed that such initial installations will be properly carried out with due consideration to the requirements of the various circuits and devices to be protected.

After such initial installation however, the user may find that because of overloading of the branch circuits, a certain breaker trips or opens automatically repeatedly, and will attempt to replace such breakers with a breaker of higher rating. Such replacement would defeat the protective function of the breaker and create a danger of lire and it is, therefore, extremely desirable that such replacement be impeded, discouraged or effectively prevented.

Accordingly, it is an important object of the present invention to provide an electric circuit panelboard of the type referred to, and circuit breakers for use therewith, wherein a circuit breaker or" a given ampere rating cannot be mounted and energized at a location Where a circuit breaker of lower ampere rating has once been inserted.

in accordance with my invention in one form, I provide a circuit breaker contact blade on the panelboard interior comprising frangible sections and circuit breakers each having a contact-blade-receiving socket therein, the socket in circuit breakers of different ratings being located in different relative positions, and in accordance with a predetermined relationship to said frangible sections of said contact blades, such that certain of said frangible portions must be removed to permit mounting certain of circuit breakers, and after removal of such frangible portions, a circuit breaker of larger ampere rating cannot thereafter be energized at such location.

My invention will be more readily understood from the toliowing description taken in connection with accompanying drawing and its scope will be pointed out in lthe appended claims.

FIGURE l is` a front elevation view of the panel board incorporating my invention, the front cover being partialiy broken away; v

FIGURE 2 is a view of the panelboard interior assembly with circuit breakers mounted thereon, taken on the line 2 2 of FlGURE 1;

FIGURE 3 is a fragmentary view in perspective and on a larger scale of the panelboard interior of FGURE 1;

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FIGURES 4, 5 and 6 are side elevation Views on enlarged scale of plug-in contact portions of circuit breakers of diiering ampere rating for use with the panel board of FIGURE 1;

FIGURE 7 is an elevation view of a plurality of circuit breakers of various ampere ratings shown in mounted position, a portion of the casings being broken away; and

FIGURE 8 is a view, on enlarged scale, of one of the contact blades of the panelboard of FIGURE l.

Referring to the drawing, l have shown my invention as embodied in a panelboard comprising a generally rectangular outer enclosure 1 having an interior assembly 2 therein for supporting a number of circuit breakers and connecting them to a source of electrical power.

The panelboard interior assembly 2 comprises a generally channel-shaped supporting pan 3 having a back wall 4 and side portions 5 provided with hook-like retaining elements 6. The support 3 is provided with two pairs of opposed apertures 7 adapted to receive return-bent end portions of resilient supporting strips 8 (only one strip shown).

A molded body of resilient insulation material 9 is mounted on the supporting pan 3 by suitable means such as by clamps lit, and has embedded therein a plurality of electrically conducting bus bars 11 arranged in iiatwise alignment edge-to-edge therein and having end portions 12 projecting therefrom and carrying line terminals 13. A generally central row of aligned contact blades 14 are provided having integral branch-connecting portions 15 extending to and preferably rigidly attached to each to one of the bus bars 11. It will be understood that the particular bus bar arrangement, as well as the insulating means employed for supporting and insulating the generally central row of contact blades 14 may be varied and if preferred, I may for instance utilize premolded insulating sections having suitable barrier portions integral therewith to support and insulate the bus bars 11 and contact blades 14.

A plurality of electric circuit breakers 16 are provided, each of which includes a recessed portion at one corner thereof, providing a retaining shelf or lug 17 adapted to be received under the retaining hooks 6. Each circuit breaker also includes a socket 18 within the insulating housing 16', adapted to cooperate with the contact blades 14. The circuit breakers 16 are adapted to be arranged in pairs in end-to-end abutting relation as indicated in FGURES 1 and 2. The socket portions 18 of each of the breakers of each of a pair is adapted to make contact with a common contact blade 14, each breaker utilizing approximately one half the contact surface thereof.

For the purpose of assuring that, after a breaker has been properly installed at a given location, no circuit breaker having a higher rating than such breaker shall subsequently be installed there, l provide the circuit breaker sockets and the Contact blades with discriminating or disabling means operating in a manner to be described. Accordingly, in accordance with my invention, each of the contact blades 14 is made so as to have three portions, as indicated at 19, 2th and 21 in FIGURE 3, The portion 21 is made frangible or easily separable from thel remaining portion of the Contact blade 14 by providing a reduced section 22 and perforations 23. The portion 2@ is likewise made frangible or separable from the remainder of the contact blade 14 by providing a reduced section 24. Perforations 23 are preferably proportioned with respect to the perforations 25 so that the portion 21 of the contact blade 14 is more easily removable than the portion 20.

The term frangible portion or its equivale-nt, in accordance with the disclosure and description hereof, is intended to mean a portion which may be readily separated upon a predetermined line of separation from the remaining body of the member of which it initially forms a part. Thus, while it is appreciated that, technically, the particular part forming the connection between the general removable portion and the remainder of the body is the part which is made frangible, the term frangible portion is used herein and in the claims to refer to a portion of a terminal or the like which may readily be broken off upon a predetermined line of separation from the remaining body of the member.

The contact-blade-receiving sockets 18 of the circuit breakers 16 each comprise contact-blade-receiving jaws 26 joined by a bridging portion 27 from which extends a Contact supporting lug portion 28. The contact-receiving socket 18 is adapted to be retained in the insulating casing of the circuit breakers by suitable means, such as by providing integral bosses 29 and by having the contact supporting lug portion 2S extending in interlocking relation with arc chute 30. It will be understood that the particular method of supporting the contact blade receiving jaw socket 18 in the circuit breaker casing may be varied somewhat and may be accomplished by various suitable means without departing from the spirit of the present invention.

For the purpose of providing a discriminating or disabling action, thel dilferent ratings of circuit breakers are provided. with contactblade receiving sockets having bridging portions 27 which are located in different respective positions in relation to the contact blades 14 when mounted in position. Preferably, the contact-blade-re ceiving sockets 18 of circuit breakers 16a of high ampere rating have bridging portions 27 located a maximum distance from the back wall 31 of the circuit breaker casing, and have adjacent contact portions located to make contact with the outermost section 21 of the Contact blade 14. Circuit breakers of an intermediate rating such, for instance, as circuit breaker 1612 are provided with a socket portion having Contact portions at a distance from the back wall of the circuit breaker casing to make contact with the portion 20 of the contact blade 14. Circuit breakers of lowest rating such as circuit breaker 16e have contact-blade-receiving sockets provided with contact portions adapted to make contact with the portion 19 of the Contact blade 14.

In a preferred embodiment of the invention as illustrated in FIGURES 4, and 6, the supporting lug 28 is preferably maintained at the same respective location in the circuit breakers of different ratings, the positioning of the contacting portions of the socket 18 in the different respective locations being accomplished by elongating the intermediate portion of the socket 18.

It will be observed that a circuit breaker of maximum rating such as 16a may be inserted onto a contact blade 14 and will make contact with the outermost portion 21 thereof without the necessity of modifying the contact blade at all. When a circuit breaker of intermediate rating such as lob is attempted to be inserted on a contact blade 1d, it will be found that because of the positioning of the socket 18, it is necessary to remove the outermost portion 21 of the contact blade 14 in order to have the circuit breaker seat fully in proper position.

While contact may be made with the outermost section of the contact blade by such breaker, the circuit breaker cannot be fuily inserted, and it will accordingly be impossible to replace the outer cover of the circuit breaker panelboard, thereby rendering it necessary to remove the outermost portion fil of the Contact blade 14. It will be appreciated that installation is, in substantialiy all accept* able cases, performed by a qualified electrician or other person whose responsibility it is to see that such breakers are properly installed. Such person can be depended on to properly install breakers initially. lt is not, primarily, misuse by such qualified personnel that is the source of most trouble, but rather the unauthorized changing and insertion of incorrectly rated devices by the user, usually CII i after some defect or overloading of wiring has caused him diificulty.

It will be observed that once the outer section 21 of the contact blade 14 is removed, if someone should attempt to insert a circuit breaker of larger ampere rating, such, for instance, as a 50 ampere circuit breaker 16a, the contact-blade-receiving socket 18 thereof will be found to be located too high to make contact with the shortened blade. Likewise, when the second section 26 has been removed in order to accommodate a low ampere rating breaker, such as breaker 16C, at a given location and thereafter an intermediate or high rated breaker is attempted to be placed at such location, the contact-blade-receiving socket portion of such intermediate and high rated breakers will also be unable to contact the modified Contact blade. Moreover', since it is an absence of connecting means rather than an obstacle or interfering object which prevents the energizing of such overrated breakers, there is no way which the user can conveniently or readily use, even with the application of force, to circumvent the discriminating and disabling means.

While I have shown a particular embodiment of my invention, it will be understood that I do not wish to be limited thereto since many modifications thereof may be made. I, therefore, contemplate by the appended claims to cover all such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electric circuit breaker panelboard comprising at lea-st one circuit breaker mounting location, circuit breaker connecting means at said location adapted to make electrical connection with a first circuit breaker mounted at said location, said circuit breaker connecting means including a first frangible portion removable to alter the dimensions of said connecting means, the remaining portion of said connecting means being unusable to make electrical connection with said first circuit breaker although not interfering with the utility of `said remaining portion of said connecting means to make connection with a second circuit breaker.

2. An electric circuit ypanelboard assembly comprising at least one circuit breaker mounting location, circuit breaker connecting means at said location usable to make electrical connection with a first circuit breaker at said location, said circuit breaker connecting means including a frangible portion removable to alter the dimensions of said connecting means to render said connecting means unusable to make connection with said rst circuit breaker, and a second electric circuit breaker mountable in said panelboard assembly in electrically connected relation to said yelectrical connecting means following removal of said frangible portion.

3. An electric circuit breaker panelboard comprising a support, a plurality of stationary contact blades projecting generally perpendicularly upward of said support, at least one circuit breaker retaining means carried by said support in spaced relation to each of said contact blades respectively, a plurality of electric circuit breakers each comprising a generally rectangular insulating casing having a mounting lug thereon at one end thereof and-a plug-in type socket at the other end thereof whereby said mounting lug may be engaged with said retaining means and said circuit breaker pivoted thereabout to bring said socket into plugin engagement with said contact blade, means for selectively and irreversibly altering the height of each of said blades in predetermined steps, said circuit breakers including at least one circuit breaker for each of said predetermined steps having the plug-in type socket thereof positioned at a corresponding predetermined height from the back wall of said breaker whereby each of said lbreakers is adapted to make contact with Contact blades only of certain predeterminedminimum height.

4. An electric circuit breaker panelboard comprising a support, a plurality of stationary contact blades projecting generally perpendicularly upward of said support, at least one circuit breaker retaining means carried by said support in spaced relation to each of said contact blades respectively, a plurality of electric circuit breakers each comprising a generally rectangular insulating casing having a mounting lug thereon at one end thereof and a plug-in type socket at the other end thereof whereby said mounting lug may be engaged with said retaining means and said circuit breaker pivoted thereabout to bring said socket into plug-in engagement with said contact blade, said contact blades having portions thereof made frangible to selectively alter the height of each of said contact blades, in predetermined steps, said circuit breakers including at least one circuit breaker for each of said predetermined steps having the plug-in type socket thereof positioned at a corresponding predetermined height from the back Wall of said breaker whereby each of said breakers is adapted to make contact With contact blades only of certain predetermined minimum height.

5. An electric circuit breaker panelboard comprising at least one circuit breaker mounting location, circuit breaker connecting means at said location for making electrical connection with a first circuit breaker, said circuit breaker connecting means including a first frangible portion removable to alter the dimensions of said connecting means, `said connecting means being unusable to make electrical connection with said first circuit breaker after removal of said first frangible portion, said connecting means being usable to make connection with a second circuit breaker after removal of said first frangible portion, said connecting means having a second frangible portion removable to further alter the dimensions of said connecting means, said connecting means being unusable to make connection with said second circuit breaker after removal of said second frangible portion, said connecting means being usable to make connection with a third circuit breaker after removal of said second frangible portion.

6. In combination, an electric circuit breaker panelboard comprising at least one circuit breaker mounting location, circuit breaker connecting means at said mounting location, said connecting means including a first removable portion removable to alter the dimensions of said connecting means, and a second portion remaining after removal of said first removable portion, a rst circuit breaker having electric terminal connecting means disposed and arranged to make contact with said first portion of said connecting means before removal thereof, a second circuit breaker having electric terminal connecting means disposed and arranged to make connection With said remaining portion of said connecting means following removal of said first portion, said first and second electric circuit breakers each including an insulating casing, said insulating casings of said iirst and second circuit breakers being substantially identical in form and dimensions, said first and second circuit breakers having their said electric terminal connecting means in different mounting locations within said insulating casing of said circuit breakers.

7. In combination, an electric circuit breaker panelboard comprising a plurality of electric circuit breaker mounting locations, panelboard connecting means at each of said mounting locations for making connection with an electric circuit breaker, said panelboard connecting means each comprising a conductive member having first and `second frangible portions successively removable to alter the effective dimension of said member, first, second and third electric circuit breakers each comprising an insulating casing and electrical connecting means carried thereby, means for mounting said circuit breakers in said panelboard, said first circuit breaker having its electrical connecting means disposed and arranged to make contact with said panelboard connecting means in unmodified form, said second circuit breaker having its electrical connecting means disposed and arranged to make Contact with said panelboard connecting means after removal of said rst frangible portion, said third circuit breaker having its electrical connecting means disposed and arranged to make contact with said panelboard connecting means after removal of said first and second frangible portions, said first circuit breaker being unusable to make contact with said panelboard connecting means after removal of said first frangible portion, and said second circuit breaker being unusable to make contact with said panelboard connecting means after removal of said first and second frangible portions.

References Cited in the tile of this patent UNITED STATES PATENTS 433,770 Cunnington Aug. 5, 1890 2,218,650 Larson Oct. 22, 1940 2,632,039 Hammerly Mar. 17, 1953 2,738,444 Casey Mar. 13, 1956 2,910,629 Casey Oct. 27, 1959 3,105,173 Kingdom Sept. 24, 1963 FOREIGN PATENTS 148,712 Germany Oct. 12, 1902 165,818 Germany Mar. 1l, 1905 414,488 Italy Aug, 7, 1946 

1. AN ELECTRIC CIRCUIT BREAKER PANELBOARD COMPRISING AT LEAST ONE CIRCUIT BREAKER MOUNTING LOCATION, CIRCUIT BREAKER CONNECTING MEANS AT SAID LOCATION ADAPTED TO MAKE ELECTRICAL CONNECTION WITH A FIRST CIRCUIT BREAKER MOUNTED AT SAID LOCATION, SAID CIRCUIT BREAKER CONNECTING MEANS INCLUDING A FIRST FRANGIBLE PORTION REMOVABLE TO ALTER THE DIMENSIONS OF SAID CONNECTING MEANS, THE REMAINING PORTION OF SAID CONNECTING MEANS BEING UNUSABLE TO MAKE ELECTRICAL CONNECTION WITH SAID FIRST CIRCUIT BREAKER ALTHOUGH NOT INTERFERING WITH THE UTILITY OF SAID REMAINING PORTION OF SAID CONNECTING MEANS TO MAKE CONNECTION WITH A SECOND CIRCUIT BREAKER. 